Liquid developing apparatus

ABSTRACT

Apparatus for developing diazo-sensitized copy material by the application thereto of a quantity of developer liquid includes an applicator roller to the surface of which there is supplied developer liquid, a wiper member mounted for engagement with the roller surface to wipe excess developer liquid therefrom and a pressure applying member mounted for engagement with the roller surface to form a developing zone therewith through which sensitized copy material is passed for development. Both the wiper and pressure applying members are movable into and out of engagement with the roller surface, depending upon the operating condition of the apparatus.

ilnited States Johnson et al.

aten

Assignee:

Filed:

1 inventors: Robert M. Johnson; Dennis E. Toby;

Robert M, Koch, all of Cleveland, Ohio Addressogrnph-MultigraphCorporation, Mount Prospect, Ill. by said Toby and Koch April 27, 1970Appl. No.: 32,314

' ..G03tl 5/06 95/89 R, 89 A, 89 L, 89 G,

References Cited UNITED STATES PATENTS ,Jons et al. ..95/89 R X1,968,911 0/19 4 Potdevin, ..l..... ....;....,..l18/261 x 2,525,92010/1950 Mackey .,....11s/261 x 3,453,138 7/1969 Chen et al ..95/89'R )1Primary Examiner-Samuel S. Matthews Assistant Examiner-Fred L. BraunAttorney-Sol L. Goldstein (This application tiled under rule 47(b)) [s71 Ans'rnmc'r Apparatus for developing diazo-sensitized copy material bythe application thereto of a quantity of developer liquid includes anapplicator roller to the surface of which there is supplied developerliquid, a wiper member mounted for engagement with the roller surface towipe excess developer liquid therefrom and a pressure applying membermounted for engagement with the roller surface to form a developing zonetherewith through which sensitized copy material is passed fordevelopment. Both the wiper and pressure applying members are movableinto and out of engagement with the roller surface, depending upon theoperating condition of the apparatus.

12 Claims, 4 Drawing Figures I 1 LIQUID DEVELOPING APPARATUS BACKGROUNDOF THE INVENTION This invention relates generally to apparatus fordeveloping diazotype copy material and more particularly to apparatus ofthe above-mentioned type which applies a liquid developing agent inmetered quantities to exposed diazo sensitized copy material, thereby toproduce dry-to-the-touch developed copies.

The method of developing diazo sensitized copy material by theapplication of relatively small, metered quantities of liquid developeris described in US. Pat. No. 3,446,620, issued May 27, 1969, andassigned to the same assignee.

Apparatus for carrying out the. above-described method is also disclosedin U.S; Pat. Applications Ser. Nos. 831,685, filed June 9, 1969, nowPat. No. 3,626,833, and831,399, filed June 9, 1969, now US. Pat. No.3,640,203 assigned to the same assignee.

' In the last-mentioned applications there is described developingapparatus comprising an applicator roller which has a uniquely p'reparedsurface adapted to receive and carry a limited quantity-of developerfluid. Against'the surfaceof the applicator roller and parallel to theaxis of rotation thereof, is a mechanical wiper used for removing excessfluid from the applicator roller surface. A second, pressure applyingroller is in driving engagement with the applicator roller to form adeveloping zone therebetween. 'Copy material fed between the rollers isdeveloped by the application of the liquid under pressure provided bythe pressure roller.

The apparatus of the aforementioned application operates well to providefully developed, dry-to-thetouch copies with a minimum of developingfluid. However, in the case wherein very wide diazo copy material (i.e.,in the range of 40 plus inches) is to be developed, applicator andpressure rollers must also be of lengths equal to or greater than thewidth of the material.

' In practice a pressure roller used in the abovedescribed apparatusweighs approximately 1 pound for each inch of length. Thus, a roller of40 plus inches would weigh 40 or more pounds. The great weight of such aroller member presents engineering problems in that added support isrequired for the roller members and greater costs for the fabrication ofsuch an apparatus would be incurred.

In addition to the last-mentioned problems, because of the length of therollers, irregularities in the surfaces, non-uniform pressurestherebetween along the lengths of the rollers and/or curves in therollers themselves which occur in fabrication or during use, might tendto produce a non-uniform application of developer fluid to copy materialpassing through the developing zone,

resulting utimately in unacceptable, non-uniformly developed copies.

SUMMARY OF THE INVENTION Accordingly, it is a general object of thepresent invention to provide new'and improved apparatus of the generaltype described for developing diazo sensitized copy material whichavoids the drawbacks discussed.

It is a more specific object of the invention to provide an apparatus ofthe lasbmentioned type which can be used successfully and efficiently inthe development of relatively wide diazo sensitized copy material byapplying uniformly thereto, a predetermined quantity of liquiddeveloping agent.

Briefly, a preferred embodiment of the developing apparatus according tothe invention comprises an applicator roller member adapted to carry alimited quantity of developer fluid and mounted for rotation. Adjacentthe surface of the applicator roller and extending the length of andparallel thereto, is a pressure applying blade mounted for tangentialengagement with the roller surface, the area between the blade androller surface forming a copy material developing zone. A second, fluidmetering blade is also mounted for tangential engagement with thesurface of the applicator roller. The second'blade is mounted about theapplicator roller from the first-mentioned blade to equalize the forcesapplied to the roller. A fluid carrying member, substantially equal inlength to the applicator roller, is located in the area between thefluid applying blade and the applicator roller. A series of holes isformed in the member, from which fluid is pumped onto the metering blademember. The fluid is dispersed by the blade member over the surface ofthe roller, andthe excess fluid wiped from the roller surface by thefluid metering blade is carried into a trough beneath the applicatorroller.

To ensure the uniform dispersion of developing fluid over the rollersurface and to prevent fluid droplets from building up in the developingzone between the applicator roller surface and the pressure applyingblade, provision is made to move the pressure applying blade, intoengagement with the roller surface a predetermined time after engagementof the wiper blade with the roller surface; sufficiently long to meter auniform layer of fluidonto the roller surface. The

latter is accomplished automatically by means of a novel electricalcircuit and control-linkage arrangement upon energization of the powerswitch of the developer apparatus. The blades are likewise removedsequentially from contact with the roller surface upon deenergization ofthe apparatus. Removal of the blades from contact with the applicatorroller surface when the developing apparatus is not in use preventsmarking of the roller surface by the blades which could detrimentallyaffect the quality of subsequent copies produced by the apparatus.

DESCRIPTION OF THE DRAWINGS A better understanding of the presentinvention and its organization and construction may be had by referringto the description below in conjunction with the accompanying drawingswherein:

FIG. 1 is a plan view of a diazotype copying machine incorporating thedeveloping apparatus according to the invention;

FIG. 2 is a side sectional view of the copying machine of FIG. 1;

FIG. 3 is an enlarged side view of the cam driver used for moving themetering and pressure applying blades of the developing apparatus intoand out of engagement with the surface of the developer fluid applicatorroller taken along the line 3-3 of FIG. I; and

FIG. 4 is a schematic diagram of the electrical circuitry for operatingthe developer apparatus in accordance with the present invention.

' DETAILED DESCRIPTION Referring now to the drawings more in detail,FIGS. 1 and 2 illustrate a diazotype copying machine 10, includingdeveloping apparatus 12 according to the invention.

The copying machine comprises a housing 14 including front and rearwalls 16, 18, upper and lower walls 20, 22, and side walls 24, 26,interconnecting the upper, lower, front and rear walls.

A lower section 28 of the housing (FIG. 2) includes copy sheet exposureapparatus 30 for exposing a diazo sensitized copy sheet to light whilethe copy sheet is in surface-to-surface contact with an originaltracing, for the purpose of imaging the copy sheet.

The particular copy sheet exposure apparatus shown in FIG. 2 of thedrawings comprises a rotatable lamp 32 about the outer surface 34 ofwhich is carried a sandwiched copy sheet and original tracing (notshown) for exposure of the former. An endless belt 36 extends about theouter surface of the lamp 32' and is also mounted for movement alongrollers 38, 30, and 42. A smaller roller44 provides tension to the belt36 to ensure that the latter is in close contact with the lamp 32.

The sandwiched original tracing and copy sheet are fed over shelf45'into an entrance 46 adjacent roller 42 between belt 36 and outersurface 34 of lamp 32. The original and copy sheet are carried aboutlamp 32 and depart at exit-48 adjacent roller 38. At this point the copysheet has been exposed. The copy sheet is separated from the originaltracing, and is now ready for development.

In the upper section 50 of the copying machine housing 14, there islocated a preferred embodiment of the developing apparatus 12 accordingto the invention.

The developing apparatus 12 comprises an applicator roller 52 having acentral shaft portion 54 of metal and an outer or peripheral layer 56 ofa smooth nonporous, resilient material such as rubber. The outer surface58 of the peripheral layer 56 is specially prepared to form a developerfluid carrier surface having irregular depressions of varying depths andsizes. A more detailed description of the carrier surface will be givenhereinafter. V

Roller 52 is mounted for rotation at ends 60, 62 of shaft portion 54between vertically extending walls 64, 66, in bearings 68, 70 mounted onthe walls (FIG. 1). An extension member 72, including a sprocket wheel74 is mounted at end 62 of shaft 54. A drive motor 76 provides the powerfor driving the applicator roller 52 through shaft 78 extending from thegear train 79 of motor 76, and including a sprocket drive wheel 80mounted thereon. An endless chain 75 connected to the aforementionedsprocket wheels serves to transfer the power provided by motor 76 to theapplicator roller 52 for rotation of the latter.

The chain 75 also extends about sprocket wheels 82, 84 which are mountedon shafts 83, 85, respectively, extending from wall 66. Thelast-mentioned wheels provide a path over which endless chain 75 movesto drive applicator roller 52.

Positioned on opposite sides of roller 52, spaced 180 from each otherthereabout, is a pair of blade members 86, 88, respectively. Each of theblade members 86, 88 is mounted on a respective rotatable support hereintaking the form of a tubular shaft 90, 92, by means of a blade holdermember 94, 96 attached thereto, respectively. The blades, eachfabricated from a flat length of spring steel or the like material, arefastened to a respective blade holder member byfasteners, such as bolts98. I

The shafts 90,92, which are also mounted between walls 64, 66 arerotatable in the direction of the arrows (FIG. 2) to cause blade members86, 88 to engage the surface 58 of roller 52, as shown in dotted lines.As can be seen, the blade members are caused to be bowed when in contactwith the roller surface to make tangential contact therewith.

A tubular conduit 100 mounted on an L shaped bracket 102, connected toblade holder member 94 is provided to dispense developer liquid to thesurface 58 of roller 52. A flexible tube 104 coupled at one end 106 ofdispenser tube 100 is connected via developer fluid pump 108 to areservoir 109 of fluid developer 110. Fluid pumped through tube-104exits from tubular conduit 100 through spaced apertures 103 (FIG. 2)provided in the wall thereof.

Developer liquid dispensed from the tube 100 is poured onto the surface112 of blade 86, and upon the latter making engagement with the surfaceof rotating roller 52, is applied or metered onto the roller surface 58.

Metering blade member 86 together with the roller 52 having thespecially prepared surface 58 delivers a controlled amount of developerfluid to a copy sheet being developed. The blade member 86 wipes awayexcess developer fluid which in turn runs back into a trough 114 mountedbeneath the applicator roller and metering blades. The excess fluid ischanneled through an opening 116 in trough 114, (FIG. 2), and through ascreen-like filter 111 to the fluid reservoir 109 so that it may bereused. The filter screen 111 serves to remove minute paper particleswhich may have found their way into the developer fluid during thedevelopment process, and which, if not removed, could eventually becomelodged beneath the blade members, causing streaks along the surface ofsubsequently developed copy sheets. Cleaning of the filter screen 111periodically to remove the paper particles build up thereon isdesirable. 5

As mentioned heretofore, the surface 58 of the applicator roller 52 isspecially prepared to carry a predetermined quantity of developer liquidused to develop diazo sensitized copy sheets.

The texture or finish of the applicator roller 52 is important to thesuccessful operation of the developer apparatus. The amount of developerfluid retained on the roller surface 58 and carried to the copy sheetbeing developed is dependent on the surface characteristics of theroller. It has been found that the surface best suited for carrying theproper amount of liquid for development of dry-to-the-touch copy sheetsis one of varying depths and sizes providing a predetermined degree ofaverage center line smoothness expressed in terms of micro-inches indepth. It has been concluded that an applicator roller having a centerline average smoothness in the range of 10-200 micro-inches provides asatisfactory finish according to the invention. The limits of fluidapplication provided by a properly prepared roller surface residebetween 0.5 grams and 3.0 grams per square meter of the copy material.

For a more detailed description of the roller surface and itspreparation, the readers attention is directed to US. Pat. applications,Ser. Nos., 831,685 and 831,399, assigned to the same assignee.

The second blade member 88, when engaged with roller surface 58, appliesto the latter surface pressure along a line of contact therewith equalto the force applied by blade member 86, l80 about the roller 52. Thecontact area forms a developing zone 118, (FIG.2) through which copysheets are passed to be developed.

It is important that the forces applied to the roller surface are equal.If they are not, a tendency for the roller to shift will be prevalent aswell as a possible disfiguration of the surface of the roller. In bothof the last-mentioned cases, the ultimate quality of copies produced inthe developer will be affected.

A copy sheet entering the developing apparatus at entrance 120 ismanually urged upwardly along curved guide member 122 mounted on fixture119 within section 51) of the-housing (FIG. 2) into the developing zone118, whereat the leading edge of the paper is gripped between thepressure applying blade member 88 and the roller 52. The rotation ofroller 52 in the direction indicated by the arrow, transports the copysheet through zone 118 whereat developer fluid is applied in printingfashion, to the imaged copy sheet. The developed copy sheet emerges fromthe developing apparatus at exit 124 in a dry-to-the-touch condition.

As mentioned heretofore, the blade members 86, 88 are each mounted onmembers 90, 92 respectively, which can be rotated to cause theengagement and disengagement of the blade members with the surface 58 ofapplicator roller 52.

The physical movement of the blade members is controlled by acontrol-linkage and electrical contact assembly 126, shown in greaterdetail in FIGS. 3 and 4 of the drawings.

The previously mentioned assembly 126 includes a control-linkage member,preferably taking the form of a cam member 128 having a generallycircular shape and mounted for rotation at the center 130 thereof to theshaft 132 of an electrically operated motor 134 (FIG. 1) capable ofbeing operated in a forward (engage) and reverse (release) direction bymeans of motor engage and release coils, respectively, to be discussedhereinafter.

Two sets of electrical contact arrangements 136, 138, each including twopairs of leaf spring contacts 136a, 136k and 138a 138b, respectively,are mounted, by means of insulating mounting arrangements 137, 139,respectively, of the well known type, adjacent cam member 128 atopposite sides thereof (180 about the circumference of the cam member).The contacts are operated by means of cam follower rollers 140, 142,connected to the stacked contacts by means of additional leaf springs143, 145, respectively. Each of the rollers rides along the externalsurface or edge 147 of the cam member 128. Lead wires as seen in'FIG. 3,are connected to the terminal ends of the respective contacts. Theactual connections to contacts 136a, 136b, and 138a, 138b will bedescribed hereinafter when discussing the circuit diagram of FIG. 4.

The cam member is constructed to include three outer track portions, T1,T2, T3, each at a different, predetermined distance measured along aradius of the cam member from the center of the latter, and along whichthe follower rollers 140, 142 ride. As the cam member 128 is rotated,contacts of the arrangements 136, 138 are opened or closed, as the casemay be, to in turn energize or deenergize motor 134.

A pair of arms 144, 146, each of which is pivotally connected at a firstend 149, 151, respectively, by fasteners 148, 150 (FIGS. 1 and 3) to arespective end 152, 154 (FIG. 1) of one of the rotatable tubular shafts90, 92, is provided to translate the rotatable movement of the cammember 128 into a driving force for movement of the blade members 86,88. The opposite ends 156, 158 of arms 144, 146 are each coupled by acam follower wheel or roller 160, 162 respectively, to cam member 128.The last-mentioned wheels being mounted for rolling engagement inspecially designed cut-outs or tracks 164, 166 in cam member 128. Eachof the tracks 164, 166 includes a passive tra'ck portion P1, P2 and anactive portion Al, A2, respectively. Movement of the rollers 160, 162along the passive portions of the tracks 164, 166, causes no physicalmovement of the respective blade members, and movement in the activeportions of tracks 164, 166 causes the blades to be moved into or out ofengagement with the applicator roller surface 58, depending upon thedirection of rotation (clockwise or counterclockwise) of cam member 128.The operation of the cam member 128 and followers will be explainedhereinafter.

Turning now to FIG. 4 of the drawings, there is illustrated therein apreferred embodiment 170 of the circuit for controlling the movement ofthe blade members 86, 88 into and out of engagement with the applicatorroller 52.

The circuit 170 is powered by a conventional 115 volt AC source, (notshown) connected across terminals 172, 174 each of which is in turnconnected to a lead 176, 178, respectively. Lead 176 is connected to afirst armature 180 of the manual operated on-off switch 182. Switcharmature 180 is normally connected to a first contact 184 which is inturn connected to a lead wire 186. The last mentioned wire 186, isconnected to normally open contacts 138a of leaf contact spring pair138.

A second contact 188 of the manual on-off switch 180 is provided forconnection with armature 180. The movement of armature 180 to contact188 supplies power via lead 183 to operate pump motor 108, thereby tobegin pumping fluid to the tube member 180 (FIG. 1) and to begin themovement of blades 86, 88. Pump motor 108 is connected back to the powersource via lead 178. The movement of switch arm 180 to contact 188 alsoprovides power from the source to energize drive motor 76 for rotatingapplicator roller 52.

The contacts 138a, connected to manual on-off switch 182 via lead 186,are connected via lead 192 to motor release coil of motor 134 which inturn is connected through lead 194, 196, back to the AC power source.

The contacts 138a are also connected to a second armature 198 ofmanually operated on-off switch 182. The armature 198 is normally in theopen position with respect to contact terminal 200 of the switch. Thelastmentioned contact terminal is connected via lead wire 202 throughswitch contacts 136b of contact pair 136, via lead 204 to the normallyclosed sets of contacts 206 of a three second time delay relay 208. Thearmature 2070f relay 208 is connected back to switch contact 188 ofswitch 182 via lead 209.

The normally open contacts 210 of relay 208 are connected via lead 212,through normally closed contacts l38b and lead 214 to motor engage coil216. The last-mentioned coil is connected back to the power source vialeads 196, 178.

Normally closed contacts 138b are connected also via lead 218 throughnormally closed contacts 136a of contact pair 136, and leads 220 and 204to the normally closed contacts 206 of time delay relay 208.

For purposes of affording a more complete understanding of theinvention, it is advantageous now to provide a functional description ofthe mode in which the component parts thus far described cooperate.

Looking again at FIG. 4, the circuit 170 as it appears, is in theunoperated, normal state. When it is desired to operate the developerapparatus of the invention, the manual on-off switch 182 is depressed,causing armature 180thereof to be moved from contact 184 to contact 188,opening the connection to lead 186 and closing operating circuits topump motor 108 drive motor 76 and a circuit via lead 109 and thenormally closed contacts 206 of time delay relay 208.

At this time applicator roller 52 starts to rotate and fluid begins tobe pumped from the reservoir v110 to tube 100 for distribution ontoblade 86 and over the surface of the applicator roller.

Power is applied through the normally closed contacts of relay 208, vialead 204 through lead 220 and normally closed contacts 136a and leads218 and 214 to the motor engage coil 216 to begin rotation of cam 128 inthe direction of arrow 224 (FIG. 3). The cam is rotated approximatelyforty degrees in the counterclockwise direction as seen in FIG. 3 to anintermediate position. As the cam turns, rollers 140, 142 roll along theedge 147 thereof.

Roller 140 remains on the track T1 for a time but then moves to trackT2, whereby contact 136a is caused to be opened. The opening of switch136a (FIG. 4) deenergizes the engage coil 216 to stop the rotation ofcam 128. At this time switch contacts 136a, l36b are both in an opencondition since roller 140 is at rest on track T2. The roller 142 alsomoves from the track T3 to T2, and causes contacts 138a to be closed. Atthis time both contacts 138a, 138b are in a closed condition.

During the forty degree rotation of cam 128, rollers 160 and 162 alsowere moved along respective cut-outs 164, 166 in cam 128. Roller 160moved along the passive portion P1 of cut-out 164 while roller 162 movedalong the active portion A2 of cut-out 166; thus, developer fluidmetering blade 86, FIG. 1, is brought into engagement with theapplicator roller surface.

During the 3 second delay time of relay 208, developer fluid flowingfrom apertures 103 in feed tube 100, is metered over the surface 58 ofroller 52. After the three second delay time is completed, relayarmature 207, moves from normally closed contact 206 to normally opencontact 210. Power from the 115 volt AC source now is provided againthrough closed contacts 138b to motor engage coil 216, once again tocause the rotation of cam member 128 in the direction (counterclockwise)of arrow 224 (FIG. 3).

The cam member 128 this time rotates an additional eighty degrees fromits intermediate position. During the eighty degree rotation, roller 142moves from track T2 to track T1, whereby switch contacts 138b areopened.

The opening of contacts 138b breaks the connection from the power sourceto the engage coil 216, deenergizing motor 134 and stopping the rotationof cam member 128.

During the last-mentioned eighty degree rotation of cam member 128,roller 162 was moved through the passive portion P2 of cut-out 166, sothat no additional movement of blade member 86 was effected. Roller 160,however, was moved through the active portion A1 of cut-out 164, causingthe pressure applying blade member 88 to be moved into engagement withthe surface of applicator roller 52.

Once both blades are in engagement with the rotating applicator roller,the developing apparatus is deemed to be in a running condition, anddiazo copies may be fed through the developer section 50 of the diazocopying machine 10 (FIG. 2) for processing.

Upon completion of the developing process, the developing apparatus isrestored to its normal unoperated state by operation of the manualon-off switch 182 to its off position. In doing so, armature 280 of theswitch is moved from engagement with contact 188 into engagement withcontact 184, and armature 198 thereof is moved out of engagement withcontact 200.

.A connection is now made from the H5 volt AC source to motor releasecoil 190. The connection is from the source via leads 176, 186, throughcontacts 138a which remain closed because of the position of roller 142on the track T1, and lead 192. With motor release coil 190 energized,motor 134 (FIG. 1) is operated to rotate cam member 128 in a clockwisedirection opposite to the direction indicated by arrow 224. The cam isrotated a full l20 back to the home or normal position.

During the last-described rotation, blade members 86, 88 aresequentially removed from engagement with the applicator roller, blademember 88 being disengaged first, followed by blade member 86. Thismovement occurs because of the movement of rollers 160, 162 through theactive and passive portions of the respective cut-outs in reverse orderfrom that explained for the initial operating cycle.

Once returned to the home position, contacts 138a are opened to stop themotor 134, and pump motor 108 is operated to an off condition.

While the preferred means for moving the blade members 86, 88 into andout of engagement with the applicator roller 52 are the cam and circuitarrangement described above, it will be understood that such sequentialmovement could be obtained by other means, such as, for example, aseries of gears arranged to control the movement of the blade memberswith a time delay arrangement operating the drive mechanism for thegears. It is therefore contemplated to cover by the present applicationany such equivalent means.

It has been explained that a preferred developing apparatus according tothe invention includes means for moving the blade members, 86, 88 intoand out of engagement with the applicator roller sequentially asdescribed. Such sequential movement is important since it affords auniform wetting of the applicator roller prior to'bringing the pressureapplying blade member into'contact with the roller, thereby to allow fora fasterstarting time as well as to prevent contact of the blade memberagainst a relatively dry roller surface which'might have a detrimentaleffect thereon. a

While it is preferred in the subject apparatus to move thepressureapplying and wiper blade members toward and away fromtheapplicator roller, the result achieved thereby can also be achievedthrough movement of the roller toward and away from the blade members,as well as through the movement of both the blades members and theroller toward and away from each other.

What we claim is: I l

1. Apparatus operable between an on and off condition for developingsensitized sheet material by the application to said material of anamount of developer liquid, said apparatus comprising: i

liquid applicator roller means mounted for rotation, said roller meanshaving a surface adapted to carry aquantity of liquid, means forsupplying said developer liquid to -said rollermeans, l 3 I wiper meansfor removing excess developer liquid from said surface of said roller,said wiper means located adjacent said roller means and mounted forengagement withsaid roller surface,

pressure applying means mounted adjacent said roller means forengagement with the surface of said roller means, said pressure applyingmeans and said roller means forming a developing zone along a line ofcontact therebetween through which said sensitized sheet material ispassed for development, and means for moving said wiper means and saidpressure applyingmeans relative to said roller means into and out ofengagement therewith.

2. Apparatus as claimed in claim 1 wherein said wiper means and pressureapplying means are moved into engagement with said applicator rollermeans in sequence.

3. Apparatus as claimed in claim 2 wherein said wiper means is movedinto engagement with said roller means prior to said pressure applyingmeans.

4. Apparatus as claimed in claim 1 wherein said pressure applying meansincludes a flat, resilient blade member mounted for tangentialengagement with said roller surface, said blade member extendingsubstantially the length of said roller means.

5. Apparatus as claimed in claim 1 wherein said wiper means comprises aflat, resilient blade member mounted for tangential engagement with thesurface of said roller means, and extending substantially the lengththereof. 6. Apparatus as claimed in claim 1 wherein said wiper means andpressure applying means are positioned at predetermined locations aboutthe circumference of said applicator roller means so as to equalize theforces applied to said roller means.

7. Apparatus as claimed in claim 6 wherein said wiper means and pressureapplying means are located at positions 180 from each other about thecircumference of said roller means.

8. Apparatus for developing sensitized sheet material by the applicationto said material of a predetermined amount of developer liquid, saidapparatus comprising:

an applicator roller mounted for rotation, said roller having a surfaceadapted to carry a predetermined quantity of developer liquid, Q meansfor supplying said developer liquid to said roller surface, wiper meansfor removing excess developer liquid from the surface of said roller,said wipermeans located adjacent said roller and mounted for movementinto and out of engagement with said roller surface, pressure applyingmeans mounted adjacent said roller for movement into and out ofengagement with said roller surface, said pressure applying means andsaid roller surface forming a developing zone along an area of contacttherebetween through which said sensitized sheet material is passed fordevelopment, and

means for moving said pressure applying means and wiper means intoengagement with said roller during the operation of said apparatus andout of engagement with said roller upon discontinuing the operation ofsaid apparatus, said means including a movable control-linkage memberconnected to said wiper means and pressure applying-means, whereby afirst movement of said member causes said wiper and pressure applyingmeans to engage said roller surface, and a second movement of saidmember causes said wiper and pressure applying means to becomedisengaged with respect to said roller surface.

9. Apparatus as claimed in claim, 8 wherein said wiper means andpressure applying means each include an elongated, flat resilient blademember, mounted on a support member adapted for movement toward and awayfrom the surface of said applicator roller, and

wherein said support members are connected to said control-linkagemember, whereby movement of said member in a first direction causes saidblade members to engage said roller surface, and movement in a seconddirection causes said blade members to become disengaged from saidroller surface.

10. Apparatus as claimed in claim 9 wherein said movement of saidcontrol-linkage member in said first direction moves said blade memberssequentially into engagement with said roller surface, said wiper meansengaging said surface prior to said pressure blade member.

11. Apparatus as claimed in claim 10 wherein said means for applyingdeveloper liquid to said roller surface includes a source of developerliquid, dispensing means in communication with said source mountedadjacent said roller means, and pump means for pumping said liquid fromsaid source to said dispensing means for distribution onto the surfaceof said roller means, and wherein said pump means is operable to pumpliquid to said dispensing means during the operation of said apparatus.

12. Apparatus for developing sensitized sheet material bytheapplicationto said materialof a predetermined amount of developer liquid, saidapparatus comprising: 5

an applicator roller mounted for rotation, said roller having a surfaceadapted to carry a predetermined quantity of developer liquid, means forsupplying said developer liquid to said roller surface, wiper means forremoving excess developer liquid from the surface of said roller, saidwiper means located adjacent said roller and mounted for a means formoving said pressure applying means and wiper means into engagement withsaid roller during the operation of said apparatus and out of engagementwith said roller upon discontinuing the operation of said apparatus,said means including a movable control-linkage member connected to saidwiper means and pressure applying means, whereby a first movement ofsaid member causes said wiper and pressure applying means to engage saidroller surface, and a second movement of said member causes said wiperand pressure applying means to become disengaged with respect to saidroller surface, and said member being connected to said pressureapplying means by a first arm member and to said wiper means by a secondarm member.

1. Apparatus operable between an on and off condition for developingsensitized sheet material by the application to said material of anamount of developer liquid, said apparatus comprising: liquid applicatorroller means mounted for rotation, said roller means having a surfaceadapted to carry a quantity of liquid, means for supplying saiddeveloper liquid to said roller means, wiper means for removing excessdeveloper liquid from said surface of said roller, said wiper meanslocated adjacent said roller means and mounted for engagement with saidroller surface, pressure applying means mounted adjacent said rollermeans for engagement with the surface of said roller means, saidpressure applying means and said roller means forming a developing zonealong a line of contact therebetween through which said sensitized sheetmaterial is passed for development, and means for moving said wipermeans and said pressure applying means relative to said roller meansinto and out of engagement therewith.
 2. Apparatus as claimed in claim 1wherein said wiper means and pressure applying means are moved intoengagement with said applicator roller means in sequence.
 3. Apparatusas claimed in claim 2 wherein said wiper means is moved into engagementwith said roller means prior to said pressure applying means. 4.Apparatus as claimed in claim 1 wherein said pressure applying meansincludes a flat, resilient blade member mounted for tangentialengagement with said roller surface, said blade member extendingsubstantially the length of said roller means.
 5. Apparatus as claimedin claim 1 wherein said wiper means comprises a flat, resilient blademember mounted for tangential engagement with the surface of said rollermeans, and extending substantially the length thereof.
 6. Apparatus asclaimed in claim 1 wherein said wiper means and pressure applying meansare positioned at predetermined locations about the circumference ofsaid applicator roller means so as to equalize the forces applied tosaid roller means.
 7. Apparatus as claimed in claim 6 wherein said wipermeans and pressure applying means are located at positions 180* fromeach other about the circumference of said roller means.
 8. Apparatusfor developing sensitized sheet material by the application to saidmaterial of a predetermined amount of developer liquid, said apparatuscomprising: an applicator roller mounted for rotation, said rollerhaving a surface adapted to carry a predetermined quantity of developerliquid, means for supplying said developer liquid to said rollersurface, wiper means for removing excess developer liquid from thesurface of said roller, said wiper means located adjacent said rollerand mounted for movement into and out of engagement with said rollersurface, pressure applying means mounted adjacent said roller formovement into and out of engagement with said roller surface, saidpressure applying means and said roller surface forming a developingzone along an area of contact therebetween through which said sensitizedsheet material is passed for development, and means for moving saidpressure applying means and wiper means into engagement with said rollerduring the operation of said apparatus and out of engagement with saidroller upon discontinuing the operation of said apparatus, said meAnsincluding a movable control-linkage member connected to said wiper meansand pressure applying means, whereby a first movement of said membercauses said wiper and pressure applying means to engage said rollersurface, and a second movement of said member causes said wiper andpressure applying means to become disengaged with respect to said rollersurface.
 9. Apparatus as claimed in claim 8 wherein said wiper means andpressure applying means each include an elongated, flat resilient blademember, mounted on a support member adapted for movement toward and awayfrom the surface of said applicator roller, and wherein said supportmembers are connected to said control-linkage member, whereby movementof said member in a first direction causes said blade members to engagesaid roller surface, and movement in a second direction causes saidblade members to become disengaged from said roller surface. 10.Apparatus as claimed in claim 9 wherein said movement of saidcontrol-linkage member in said first direction moves said blade memberssequentially into engagement with said roller surface, said wiper meansengaging said surface prior to said pressure blade member.
 11. Apparatusas claimed in claim 10 wherein said means for applying developer liquidto said roller surface includes a source of developer liquid, dispensingmeans in communication with said source mounted adjacent said rollermeans, and pump means for pumping said liquid from said source to saiddispensing means for distribution onto the surface of said roller means,and wherein said pump means is operable to pump liquid to saiddispensing means during the operation of said apparatus.
 12. Apparatusfor developing sensitized sheet material by the application to saidmaterial of a predetermined amount of developer liquid, said apparatuscomprising: an applicator roller mounted for rotation, said rollerhaving a surface adapted to carry a predetermined quantity of developerliquid, means for supplying said developer liquid to said rollersurface, wiper means for removing excess developer liquid from thesurface of said roller, said wiper means located adjacent said rollerand mounted for movement into and out of engagement with said rollersurface, pressure applying means mounted adjacent said roller formovement into and out of engagement with said roller surface, saidpressure applying means and said roller surface forming a developingzone along an area of contact therebetween through which said sensitizedmaterial is passed for development, and means for moving said pressureapplying means and wiper means into engagement with said roller duringthe operation of said apparatus and out of engagement with said rollerupon discontinuing the operation of said apparatus, said means includinga movable control-linkage member connected to said wiper means andpressure applying means, whereby a first movement of said member causessaid wiper and pressure applying means to engage said roller surface,and a second movement of said member causes said wiper and pressureapplying means to become disengaged with respect to said roller surface,and said member being connected to said pressure applying means by afirst arm member and to said wiper means by a second arm member.